Carbon supported cobalt and molybdenum catalyst

ABSTRACT

The present invention relates to a catalyst composition comprising cobalt molybdenum and optionally one or more elements selected from the group consisting of alkali metals and alkaline earth metals on a carbon support wherein said cobalt and molybdenum are in their metallic form. It was surprisingly found that the selectivity for alcohols can be increased by using the carbon supported cobalt molybdenum catalyst as described herein in a process for producing alcohols from a feed stream comprising hydrogen and carbon monoxide. Furthermore, it was found that the catalyst of the present invention has a decreased selectivity for CO 2  and can be operated at relatively low temperature when compared to conventional catalysts. Moreover, a method for preparing the carbon supported cobalt molybdenum catalyst composition and a process for producing alcohols using said carbon supported cobalt molybdenum catalyst composition is provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/006,199, filed Jan. 31, 2014, which is a U.S. National PhaseApplication of International Application No. PCT/EP2012/001699, filedApr. 19, 2012, which claims priority to European Patent Application No.11003260.4, filed Apr. 19, 2011, which applications are all incorporatedherein fully by this reference.

The present invention relates to a catalyst composition comprisingcobalt molybdenum and optionally one or more elements selected from thegroup consisting of alkali metals and alkaline earth metals on a carbonsupport wherein said cobalt and molybdenum are in their metallic form.It was surprisingly found that the selectivity for alcohols can beincreased by using the carbon supported cobalt molybden urn catalyst asdescribed herein in a process for producing alcohols from a feed streamcomprising hydrogen and carbon monoxide. Furthermore, it was found thatthe catalyst of the present invention has a decreased selectivity forCO₂ and can be operated at relatively low temperature when compared toconventional catalysts. Moreover, a method for preparing the carbonsupported cobalt molybdenum catalyst composition and a process forproducing alcohols using said carbon supported cobalt molybdenumcatalyst composition is provided.

Gaseous mixtures comprising hydrogen (H₂) and carbon monoxide (CO) canbe converted into a hydrocarbon product stream by a catalytic processknown as Fischer-Tropsch synthesis (F-T synthesis). The most commoncatalysts useful in F-T synthesis (“F-T catalysts”) are based on Feand/or Co, although Ni- and Ru-based catalysts have also been described(see e.g. U.S. Pat. No. 4,177,203; Commereuc (1980) J. Chem. Soc., Chem.Commun. 154-155; Okuhara (1981) J. Chem. Soc., Chem. Commun. 1114-1115).Generally, Ni-based catalysts are relatively more selective forproducing methane whereas Co-, Fe- and Ru-based catalysts are moreselective for hydrocarbons having at least two carbon atoms (C2+hydrocarbons). Moreover, the selectivity for C2+ hydrocarbons can beincreased by decreasing the H₂:CO ratio, decreasing the reactiontemperature and decreasing the reactor pressure.

It has been previously described that alcohols may be produced by F-Tsynthesis using a catalyst composition having as a first componentmolybdenum in free or combined form, as a second component a promoter ofan alkali or alkaline earth element in free or combined form and as athird component cobalt in free or combined form (see EP 0 172 431 A2).Preferably, the first and third component is present as the sulphide.The catalyst of EP 0 172 431 A2 may further comprise a support, whereincarbon supports are preferred.

WO 2010/002618 A1 describes a catalyst comprising elemental molybdenum,cobalt or their alloy and an alkali or alkaline earth metal and/orhybrids thereof, in an elemental ratio of about 2-1:1:0.08-0.30, carriedon a porous, inert particularized material and the use of said catalystin a process for making alcohols by passing syngas through a reactorcontaining said catalyst. The preferred support used for the catalystaccording to WO 2010/002618 A1 is alumina, wherein the catalyst has asurface area of about 210 m²/g.

A major drawback of conventional catalysts for producing alcohols by F-Tsynthesis is that the selectivity of the process for alcohols isrelatively low.

It was an object of the present invention to provide an improvedcatalyst suitable for producing alcohols from a syngas mixturecomprising hydrogen and carbon monoxide.

The solution to the above problem is achieved by providing theembodiments as described herein below and as characterized in theclaims. Accordingly, the present invention provides a catalystcomposition comprising cobalt (Co); and molybdenum (Mo) on an activatedcarbon support (C) wherein the relative molar ratios of the elementscomprised in said composition are represented by the formula:Co_(a)Mo_(b)M_(c)C

wherein:

-   -   M is one or more elements selected from the group consisting of        alkali metal and alkaline earth metal;    -   a is 1E−3-0.3;    -   b is 1E−3-0.9    -   c is 0-1E−2; and

wherein said Co and Mo are in their metallic form and wherein thecatalyst composition has a BET surface area of at least 320 m²/g.

In the context of the present invention, it was surprisingly found thatboth the CO conversion and the selectivity for alcohols can be increasedby using the activated carbon supported cobalt molybdenum catalyst asdescribed herein in a process for producing alcohols from a feedstreamcomprising hydrogen and carbon monoxide. Furthermore, it was found thatthe catalyst of the present invention has a decreased selectivity forCO₂ and can be operated at relatively low temperature in a process forproducing alcohols from a syngas mixture comprising hydrogen and carbonmonoxide when compared to conventional catalysts. It was found thatparticularly the specific combination of the metallic Co and Mo and theselection of a carbon supported catalyst composition having a BETsurface area of at least 320 m²/g leads to the advantageous effects ofthe present invention.

The present invention accordingly relates to an activated carbonsupported cobalt and molybdenum catalyst composition wherein thecomprised Co and Mo are in their metallic form. This means that at least90 mole-%, more preferably at least 95 mole-% and most preferably atleast 99 mole-% of the Co and Mo comprised in the catalyst compositionhave the oxidation state “zero” (0).

Preferably, the Co and/or Mo comprised in the catalyst composition ofthe invention are not in sulphide form. This means that the catalystcomposition of the present invention has not been sulphided with e.g.H₂S as taught in EP 0 172 431 A2.

Furthermore, it was surprisingly found that a carbon supported catalystcomposition has both an improved CO conversion and alcohol selectivityin case the BET surface area of said catalyst composition is at least320 m². The surface area of the catalyst composition inter alia dependson the surface area of the activated carbon support particles and thecalcination temperature used when preparing the catalyst composition.Preferably, the catalyst composition has a BET surface area of 320-1500m²/g, more preferably of 320-1200 m²/g, even more preferably of350-1200, particularly preferably of 350-1000 and most preferably of350-800 m²/g.

The term “BET surface area” is a standardized measure to indicate thespecific surface area of a material which is very well known in the art.Accordingly, the BET surface area as used herein is measured by thestandard BET nitrogen test according to ASTM D-3663-03, ASTMInternational, October 2003.

The amount of Co present in the catalyst composition is determined bythe molar ratio of Co in relation to the carbon support C in thecatalyst composition. The molar ratio of Co:C is 1E−3-0.3:1 (alsodepicted as: Co_(a)C wherein a is 1E−3-0.3:1 or 0.001-0.3:1). This meansthat the molar ratio of Co:C is between 1E−3:1 (or 0.001:1) and 0.3:1.Most preferably, the molar ratio of Co:C is 1E−2-0.3. It was found thatwhen the catalyst composition comprises too much Co, the catalyticactivity shifts towards hydrogenation which decreases catalystselectivity for oxygenates and increases catalyst selectivity fornon-oxygenated hydrocarbons.

The amount of Mo present in the catalyst composition is determined bythe molar ratio of Mo in relation to the carbon support C in thecatalyst composition. The molar ratio of Mo:C is 1E−3-0.9:1 (alsodepicted as: Mo_(b)C wherein b is 1E−3-0.9:1 or 0.001-0.9:1). This meansthat the molar ratio of Mo:C is between 1E-3:1 (or 0.001:1) and 0.9:1.Most preferably, the molar ratio of Mo:C is 5E−3-0.2. It was found thatselectivity of the catalyst for CO₂ is increased when the catalystcomposition comprises too much Mo. Moreover, it was found that theselectivity of the catalyst for oxygenates decreased when the catalystcomprises too little Mo.

Preferably, the molar ratio of Co:Mo is 1 or more. It was surprisinglyfound that catalyst selectivity for oxygenates is increased when themolar ratio of Co:Mo is 1 or more. More preferably, the molar ratio ofCo:Mo is 1.2-4, even more preferably 1.5-3, particularly preferably2-2.5 and most preferably 2.1-2.3.

The catalyst composition of the present invention may further compriseone or more elements selected from the group consisting of alkali metaland alkaline earth metal (depicted herein as “M”). Preferably, the oneor more alkali metals that may be comprised in the catalyst compositionare selected from the group consisting of sodium (Na), potassium (K),rubidium (Rb) and caesium (Cs), more preferably selected from the groupconsisting of sodium (Na), potassium (K) and caesium (Cs), and mostpreferably is potassium (K). The one or more alkaline earth metals thatmay be comprised in the catalyst composition are preferably selectedfrom the group consisting of magnesium (Mg), calcium (Ca), strontium(Sr) and barium (Ba), and more preferably selected from the groupconsisting of magnesium (Mg) and calcium (Ca).

The amount of M present that may be present in the catalyst compositionis determined by the molar ratio of M in relation to the carbon supportC in the catalyst composition. The molar ratio of M:C is 0-1E−2 (alsodepicted as: M_(c)C wherein c is 0-1E−2:1 or 0-0.01:1). This means thatthe molar ratio of M:C is between 0 and 1E−2:1 (or 0.01:1). Preferably,the molar ratio of M:C is >0-1E−2. The term “>0” means that M must bepresent in the catalyst composition. Most preferably, the molar ratio ofM:C is 1E−4-1E−2. Without being bound by theory, it is believed that theconcentration of alkali and alkaline earth metals can affect theweakening or strengthening of C—O bonds. Accordingly, the presence of anelectron-donating species on the catalyst surface may suppress theadsorption of hydrogen because hydrogen itself donates an electron tometal upon adsorption. Furthermore, heat of adsorption of hydrogen maydecrease with an increase in alkali metal and/or alkaline earth metalwhich confirms that addition of M may suppresses adsorption of hydrogenin a certain range. As a result thereof, the catalyst the selectivity todesired products may be enhanced in case a critically requiredconcentration of alkali metal and/or alkaline earth metal is comprisedin the catalyst composition.

The catalyst composition of the present invention is preferably formedin regularly sized particles such as conventionally formed catalystpellets and/or sieved catalyst particles. The catalyst composition ofthe present invention may comprise further components including but notlimited to binders and lubricants. Any inert catalyst binder may beused. Preferably, the binder is selected from the group consisting ofbentonite clay, colloidal silica and kaolin. Suitable lubricants areselected from the group consisting of hydrogenated cottonseed oil andhydrogenated soybeen oil.

In a further embodiment, the present invention relates to a method forpreparing the catalyst composition as described herein, wherein saidmethod comprises the steps of:

-   (a) preparing a mixture comprising activated carbon support    particles having a BET surface area of 700-1500 m²/g and a solution    comprising soluble Co- and Mo-comprising salts;-   (b) precipitating the Co and Mo by converting the soluble Co- and    Mo-comprising salts into insoluble Co- and Mo-comprising salts,    optionally followed by admixing a solution comprising M;-   (c) separating the solids from the liquid to obtain the catalyst    precursor; and-   (d) contacting the catalyst precursor with a reducing agent at a    temperature of 300-550° C.

Preferably, the step of contacting the catalyst precursor with areducing agent comprises the steps of:

-   (d1) calcining the catalyst precursor in an inert atmosphere to    obtain the calcined catalyst precursor; and-   (d2) contacting the calcined catalyst precursor with a reducing    agent.

Preferably, the activated carbon support particles have a specificsurface area of 700-1500 m²/g, more preferably of 800-1200 m²/g, evenmore preferably of 800-1000 m²/g and most preferably of 800-900 m²/g.Carbon catalyst support particles are very well known in the art and maybe prepared from coals and coal-like materials, petroleum-derivedcarbons and plant-derived carbons (see Auer (1998) Applied Catal259-271). Most preferably, the carbon support particles used in thepresent method is derived from coconut shell carbon and has a specificsurface area of 800-900 m²/g.

In the cobalt-molybdenum-solution preparation step (a) as describedherein, a solution comprising soluble cobalt- and molybdenum-comprisingsalts is prepared. The solvent and the obtained solution may be heatedto facilitate dissolving of the cobalt- and molybdenum-comprising salts.Preferably, the solvent and the obtained solution is heated to at least60° C. and up to 95° C. (60-95° C.), most preferably to 75-85° C. Thecobalt-molybdenum-solution may be made in any suitable solvent. Suitablesolvents are all compounds in which the chosen salts are soluble andwhich are easy to remove again in the separation step as defined herein.Aqueous solutions, however, are preferred. Most preferably, the solventis water (H₂O).

In the precipitate forming step (b) as described herein, a precipitateis formed by converting the soluble cobalt- and molybdenum-comprisingsalts into insoluble compounds, e.g. by admixing an alkaline solution asprecipitant, preferably under constant agitation. Preferably, theprecipitate is formed by admixing a suitable amount of ammoniumhydroxide to a cobalt-molybdenum-solution. The amount of alkalinecompound present in the alkaline solution is selected so that it is atleast sufficient for the stoichiometric reaction with the solublecobalt- and molybdenum-comprising salts present. Preferably, the amountof alkaline compound present in the alkaline solution is 1-10 times thestoichiometric required amount. Preferably, the ammonium hydroxide isheated to the same temperature as the cobalt-molybdenum-solution. The pHat the end of the precipitation step preferably is at least 8, morepreferably at least 9. The temperature of the mixture may be keptconstant until the precipitate is formed, preferably under constantagitation. It was surprisingly found that the catalyst selectivitypattern of alcohols depends on the pH of precipitation mixture and theconcentration of precipitant. The pH difference and concentration of theprecipitant also affects the morphology of catalyst material.

The method for preparing the catalyst composition according to thepresent invention also covers a method wherein first a solutioncomprising a soluble Co-comprising salt is prepared and a Co-comprisingprecipitate is formed as described herein above wherein subsequently asoluble Mo-comprising salt is dissolved and precipitated. Alternatively,the method for preparing the catalyst composition according to thepresent invention also covers a method wherein first a solutioncomprising a soluble Mo-comprising salt is prepared and a Mo-comprisingprecipitate is formed wherein subsequently a soluble Co-comprising saltis dissolved and precipitated.

Optionally, a solution of a salt comprising one or more elementsselected from the group consisting of the alkali metal elements and thealkaline earth metal elements is admixed to the solution comprising theprecipitate, preferably under continuous agitation, to form a modifiedprecipitate. The solutions used to modify the precipitate may be made inany suitable solvent. Aqueous solutions, however, are preferred. Mostpreferably, the solvent is water (H₂O).

In the precipitate separation step (c) as described herein, the formedprecipitate (i.e. the solid phase of the mixture that is formed aftercompleting the modified precipitate forming step (b)) is separated fromthe liquid (i.e. the liquid phase of the mixture that is formed aftercompleting the precipitate forming step (b)) using any conventionalmethod which allows the separation of a precipitate from a solvent.Suitable methods include, but are not limited to, filtering, decantingand centrifugation. Subsequently the obtained catalyst precursor may bewashed, preferably using the solvent in which the solutions were made,more preferably with water, most preferably with distilled water. Thecatalyst precursor then may be dried, preferably at 110-120° C. for 4-16hours.

In the calcining step (d1) as described herein, the catalyst precursoris calcined in an inert atmosphere to form a calcined catalystprecursor. Preferably, the catalyst precursor is calcined at 450-650° C.for 5-10 hrs for 4-24 hours. The skilled person is readily capable ofselecting a suitable inert gas to form the inert atmosphere. Preferredinert gases are selected from the group consisting of nitrogen andhelium.

After calcination, the calcined catalyst precursor may be formed intopellets using any conventional method. Said pellets may subsequently besieved to obtain regularly sized particles. Said particles may be sizedbetween 0.65-0.85 mm.

In the reducing step (d) or (d2) as described herein, the calcinedcatalyst precursor is contacted with a reducing agent. This is to reducethe comprised Co and Mo to its metallic state and results in theformation of metallic Co and Mo as comprised in the catalyst compositionas defined herein. Any suitable reducing agent may be used in thereducing step of this invention. Preferably, the reducing step isperformed using a reducing agent in the gas phase. The preferredreducing agent is selected from the group consisting of hydrogen (H₂)and carbon monoxide (CO). The reduction can be carried out at ambienttemperature or at elevated temperature. Preferably, the reduction iscarried out at a temperature of at least 300° C., more preferably of atleast 350° C. and up to 550° C., more preferably up to 500° C.Preferably, calcined catalyst precursor is contacted with a reducingagent for at least 14 hrs, more preferably for at least 16 hrs and up to24 hrs, more preferably up to 20 hrs.

Preferably, the reducing step is performed “in situ”. The term “in situ”is well known in the field of chemical engineering and refers toindustrial plant operations or procedures that are performed in place.For example, aged catalysts in industrial reactors may be regenerated inplace (in situ) without being removed from the reactors; see e.g. WO03/041860 and WO 03/076074. In the context of the present invention,accordingly, a catalyst composition that is reduced in situ refers to acatalyst composition wherein the reducing step is performed in place,i.e. in the same enclosure that is later present in the processinstallation in which the catalysed process takes place. In oneembodiment, the reducing step as defined herein is performed while the“calcined catalyst precursor” is already present in the catalystenclosure that is situated in the process installation wherein thecatalyst composition is to be employed. In a further embodiment, thereducing step as defined herein is performed while the “calcinedcatalyst precursor” is already present in the catalyst enclosure whichcan be directly placed into said process installation.

In a further embodiment of the present invention a catalyst compositionobtainable by the herein above described method for preparing a catalystcomposition is provided. Accordingly, the present invention relates to acatalyst composition obtainable by the method comprising the steps:

-   (a) preparing a mixture comprising activated carbon support    particles having a BET surface area of 700-1500 m²/g and a solution    comprising soluble Co- and Mo-comprising salts;-   (b) precipitating the Co and Mo by converting the soluble Co- and    Mo-comprising salts into insoluble Co- and Mo-comprising salts,    optionally followed by admixing a solution comprising M;-   (c) separating the solids from the liquid to obtain the catalyst    precursor; and-   (d) contacting the catalyst precursor with a reducing agent at a    temperature of 300-550° C.

In a further embodiment, the present invention relates to a process forproducing a product stream comprising alcohols comprising contacting thecatalyst composition as described herein with a gaseous mixturecomprising hydrogen and carbon monoxide (syngas mixture). The productstream comprising alcohols is preferably produced by Fischer-Tropschsynthesis.

The terms “alcohols” is very well known in the art. Accordingly, an“alcohol” relates to any hydrocarbon compound in which a hydroxylfunctional group (—OH) is bound to a carbon atom, usually connected toother carbon or hydrogen atoms. Preferred alcohols comprised in theproduct stream of the present process are C1-C4 alcohols, such asmethanol, ethanol, propanol and 1-butanol.

In the context of the present invention, it was surprisingly found thatthe process for producing alcohols from a feedstream comprising hydrogenand carbon monoxide as described herein has an increased selectivity foralcohols and a decreased selectivity for the undesired by-product CO₂.Furthermore, it was found that the process of the present invention canbe operated at relatively low temperature which allows a morecost-effective operation.

In the process of the present invention, the catalyst composition ispreferably comprised in a fixed bed reactor or a fluidized bed reactor.

Preferably, the syngas mixture has a hydrogen (H₂) to carbon monoxide(CO) molar ratio of 0.5-5 (i.e. H₂:CO is 1:0.5 to 1:5). Preferably, thesyngas mixture has a hydrogen (H₂) to carbon monoxide (CO) molar ratioof 1-4 (i.e. H₂:CO is 1:1 to 1:4). The term “syngas mixture” as usedherein relates to a gaseous mixture substantially consisting of hydrogen(H₂) to carbon monoxide (CO). The syngas mixture, which is used as afeed stream to the present process for producing alcohols, may compriseup to 10 mol-% of other components such as CO₂ and lower hydrocarbons(lower HC, such as methane). Said other components may be side-productsor unconverted products obtained in the process used for producing thesyngas mixture. Preferably, the syngas mixture comprises substantiallyno molecular oxygen (O₂). As used herein, the term “syngas mixturecomprising substantially no O₂” relates to a syngas mixture whichcomprises such a low amount of O₂ so that the comprised O₂ does notinterfere with the Fischer-Tropsch synthesis reaction. Preferably, thesyngas mixture comprises not more than 1 mol-% O₂, more preferably notmore than 0.5 mol-% O₂ and most preferably not more than 0.4 mol-% O₂.

The process conditions useful in the process of the present inventioncan be easily determined by the person skilled in the art; see Dry(2004) Stud. Surf. Sci. Catal 152:197-230 in “Fischer-Tropschtechnology” eds. Steynberg and Dry. Accordingly, the Fischer-Tropschsynthesis is performed at a reaction temperature of 150-450° C.,preferably of 150-350° C., a space velocity of 400-5000 h⁻¹, preferablyof 2000 h⁻¹ and a pressure of between atmospheric and 20 MPa, preferablya pressure of 1-8 MPa. The catalyst may be stabilized for 80-100 hoursat 150-350° C. before actual use.

In this respect, it should be noted that the reaction conditions have amarked effect on the catalytic performance. It has been reported thatselectivity on a carbon basis is essentially a function of theprobability of chain growth, α; see Dry (2004) loc. cit. Control of theproduct selectivity is to a large extent determined by the factors thatinfluence the value of α. The main factors are the temperature of thereaction, the gas composition and more specifically the partialpressures of the various gases in contact with catalyst inside thereactor. Overall, by manipulating these factors a high degree offlexibility can be obtained regarding the type of product and the carbonrange. An increase in FT-synthesis operating temperature shifts theselectivity profile to lower carbon number products. Desorption ofgrowing surface species is one of the main chain termination steps andsince desorption is an endothermic process so a higher temperatureshould increase the rate of desorption which will result in a shift tolower molecular mass products. Similarly, the higher the CO partialpressure the more is the catalyst surface covered by adsorbed monomers.The lower the coverage by partially hydrogenated CO monomers the higherthe probability of chain growth is expected to be; see also Mirzaei etal., Adv. Phys. Chem., 2009, 1-12. Accordingly, the two key stepsleading to chain termination are desorption of the chains yieldingunsaturated hydrocarbons and hydrogenation of the chains to yieldsaturated hydrocarbons.

In the context of the present invention, it was surprisingly found thatthe catalyst of the present invention has an improved activity atrelatively low reaction temperatures. Accordingly, the process of thepresent invention can be very efficiently operated at a reactiontemperature of 250° C. which is significantly lower than the optimalreaction temperature of a conventional F-T process for producingalcohols.

In a further embodiment, the present invention relates to a process forproducing a product stream comprising alcohols comprising the method forpreparing the catalyst composition as described herein and contactingthe obtained catalyst composition with a syngas mixture.

In the present invention, the product stream comprising alcohols ispreferably produced by Fischer-Tropsch synthesis.

Accordingly, the present invention provides a process for producing aproduct stream comprising alcohols, preferably by Fischer-Tropschsynthesis, comprising:

-   (a) preparing a mixture comprising activated carbon support    particles having a BET surface area of 700-1500 m²/g and a solution    comprising soluble Co- and Mo-comprising salts;-   (b) precipitating the Co and Mo by converting the soluble Co- and    Mo-comprising salts into insoluble Co- and Mo-comprising salts,    optionally followed by admixing a solution comprising M;-   (c) separating the solids from the liquid to obtain the catalyst    precursor; and-   (d) contacting the catalyst precursor with a reducing agent at a    temperature of 300-550° C.

MODE(S) FOR CARRYING OUT THE INVENTION

The present invention will now be more fully described by the followingnon-limiting Examples.

EXAMPLE 1 (COMPARATIVE)

CoMoS₂

A co-precipitated cobalt/molybdenum sulfide is prepared with a Mo/Coatomic ratio of about 2:1. Fifteen grams of (NH₄)₆Mo₇O₂₄.4H₂O (0.085Moles Mo) is dissolved in 106 cm³ of 22% (NH₄)₂S in water and stirred at60° C. for one hour to form (NH₄)₂MoS₄. A solution of 10.5 grams of Co(CH₃CO₂)₂ (0.042 moles Co) in 200 ml of water was prepared. The twosolutions were then added simultaneously, drop wise to a stirredsolution of 30% aqueous acetic acid in a baffled flask at 50° C. over aone hour period. After stirring for an additional hour the reactionmixture is filtered and the filter cake dried at room temperature andthen calcined for one hour at 500° C. in an inert atmosphere such asnitrogen. The calcined Co/Mo Sulfide is ground together with 2.0 g ofbentonite clay, 1.0 g of K₂CO₃ and 0.4 g of sterotex lubricant in amortar and pestles and used for catalyst testing.

EXAMPLE 2

Co_(0.159)Mo_(0.079)C

100 ml each of Co and Mo solutions was prepared by dissolving 10.5 g ofcobalt acetate [Co(CH₃CO₂)₂] and 15 g of ammonium molybdate tetrahydrate[(NH₄)₆Mo₇O₂₄.4H₂O] in distilled water. Both solutions were premixed andheated to 80° C. The NH₃ precipitating solution (200 ml of 11.6 M NH₃solution) was also preheated to 80° C. 6.4 g of activated carbon(derived from coconut shell having a BET surface area of 800 m²/g) wasadded into 100 ml of distilled water in the precipitation vessel. Bothreagents (mixed metal salts solutions and NH₃ solution) were combinedtogether in the reaction vessel at 80° C. at a combined pumping rate of6.7 ml/min (3.3 ml/min NH₃ solution, 3.3 ml/min metals solution). Thereagents were combined in the reaction vessel (80° C.) containingactivated carbon in 100 ml of water. The pH was varied from 4.35-8.00.The duration of reaction was 1 h. This solution was immediately filteredthrough a preheated funnel and washed (using 500 ml of warm distilledwater). The precipitates were dried at 110° C. for 16 h followed bycalcinations at 500° C. under continuous flow of helium for 24 h. Thecalcined catalysts were pelleted and sieved (0.65-0.85 mm).

EXAMPLE 3

Co_(0.159)Mo_(0.079)C

100 ml each of Co and Mo solutions was prepared by dissolving 10.5 g ofcobalt acetate [Co(CH₃CO₂)₂] and 15 g of ammonium molybdate tetrahydrate[(NH₄)₆Mo₇O₂₄.4H₂O] in distilled water. Both solutions were premixed andheated to 80° C. The NH₃ precipitating solution (200 ml of 5.6M NH₃solution) was also preheated to 80° C. 6.4 g of activated carbon(derived from coconut shell having a BET surface area of 800 m²/g) wasadded into 100 ml of distilled water in the precipitation vessel. Bothreagents (mixed metal salts solutions and NH₃ solution) were combinedtogether in the reaction vessel at 80° C. at a combined pumping rate of6.7 ml/min (3.3 ml/min NH₃ solution, 3.3 ml/min metals solution). Thereagents were combined in the reaction vessel (80° C.) containingactivated carbon in 100 ml of water. The pH was varied from 4.35-9.00.The duration of reaction was approximately 1 h. This solution wasimmediately filtered through a preheated funnel and washed (using 500 mlof warm distilled water). The precipitates were dried at 110° C. for 16h followed by calcinations at 500° C. under continuous flow of heliumfor 24 h. The calcined catalysts were pelleted and sieved (0.65-0.85mm).

EXAMPLE 4

Co_(0.126)Mo_(0.766)C

100 ml each of Co and Mo solutions was prepared by dissolving 10.5 g ofcobalt acetate [Co(CH₃CO₂)₂] and 45.08 g of ammonium molybdatetetrahydrate [(NH₄)₆Mo₇O_(24.4)H₂O] in distilled water. Both solutionswere premixed and heated to 80° C. The NH₃ precipitating solution (200ml of 5.6M NH₃ solution) was also preheated to 80° C. 4 g of activatedcarbon (derived from coconut shell having a BET surface area of 800m²/g) was added into 100 ml of distilled water in the precipitationvessel. Both reagents (mixed metal salts solutions and NH₃ solution)were combined together in the reaction vessel at 80° C. at a combinedpumping rate of 6.7 ml/min (3.3 ml/min NH₃ solution, 3.3 ml/min metalssolution). The reagents were combined in the reaction vessel (80° C.)containing activated carbon in 100 ml of water. The pH was varied from4.35-9.00. The duration of reaction was approximately 1 h. This solutionwas immediately filtered through a preheated funnel and washed (using500 ml of warm distilled water). The precipitates were dried at 110° C.for 16 h followed by calcinations at 500° C. under continuous flow ofhelium for 24 h. The calcined catalysts were pelleted and sieved(0.65-0.85 mm).

EXAMPLE 5

Co_(0.177)Mo_(0.547)C

100 ml each of Co and Mo solutions was prepared by dissolving 14.7 g ofcobalt acetate [Co(CH₃CO₂)₂] and 32.2 g of ammonium molybdatetetrahydrate [(NH₄)₆Mo₇O₂₄.4H₂O] in distilled water. Both solutions werepremixed and heated to 80° C. The NH₃ precipitating solution (200 ml of5.6M NH₃ solution) was also preheated to 80° C. 4 g of activated carbon(derived from coconut shell having a BET surface area of 800 m²/g) wasadded into 100 ml of distilled water in the precipitation vessel. Bothreagents (mixed metal salts solutions and NH₃ solution) were combinedtogether in the reaction vessel at 80° C. at a combined pumping rate of6.7 ml/min (3.3 ml/min NH₃ solution, 3.3 ml/min metals solution). Thereagents were combined in the reaction vessel (80° C.) containingactivated carbon in 100 ml of water. The pH was varied from 4.35-9.00.The duration of reaction was approximately 1 h. This solution wasimmediately filtered through a preheated funnel and washed (using 500 mlof warm distilled water). The precipitates were dried at 110° C. for 16h followed by calcinations at 500° C. under continuous flow of heliumfor 24 h. The calcined catalysts were pelleted and sieved (0.65-0.85mm).

Catalyst Testing

Catalyst material (0.5 g) were loaded in a reactor and reduced with H₂at 350-400° C. for several hours. Pressure was increased to 75 bar. Allcatalysts were tested under similar reaction conditions (T=250° C.; p=75bar; and WHSV=1225 h⁻¹). The composition of the feed stream wasCO:H₂:N₂=47.5:47.5:5. Accordingly, the feedstream comprised syngashaving CO:H₂ molar ratio of 1.

Analysis of gaseous product was achieved by an online gas chromatograph(GC, Varian 3800). A 5 m*⅛ inch stainless steel Porapak-Q column (meshsize 80-100) was used to separate the reactants and products.Concentrations of hydrogen, carbon monoxide, carbon dioxide and nitrogenwere analyzed by a thermal conductivity detector (TCD). The TCD comparesthe conductivity of the analyzed gas to that of a reference gas.Conversion was determined using an internal standard, nitrogen. Organiccompounds such as hydrocarbons and oxygenates were determined by a flameionization detector (FID). By using a hydrogen and air flame, the FIDburns the organic compounds into ions whose amounts are roughlyproportional to the number of carbon atoms present. Liquid products fromalcohols reactor were collected and identified by gas chromatographymass spectrometer (GC-MS, Perkin Elmer TurboMass). Quantification ofliquid products was determined by an offline GC equipped with aChrompack capillary column (CP-Sil 8CB, 30 m, 0.32 mm, 1 μm) and an FIDdetector.

The provided values have been calculated as follows:

Conversion:

An indication of the activity of the catalyst was determined by theextent of conversion of the carbon monoxide or for more active catalystsby the extent of volume reduction of the reagent gases (using nitrogenas internal standard). The basic equation used was:Conversion %=Moles of CO_(in)−moles of CO_(out)/moles of CO_(in)*100/1

Selectivity

First of all, the varying response of the detector to each productcomponent was converted into % v/v by, multiplying them with onlinecalibration factors. Then these were converted into moles by takingaccount the flow out of internal standard, moles of feed in and time inhours. Moles of each product were converted into mole-% andselectivity-% was measured by taking carbon numbers into account.

TABLE 1 Example 1 2 3 4 5 Catalyst CoMoS₂ Co_(0.159)Mo_(0.079)CCo_(0.159)Mo_(0.079)C Co_(0.126)Mo_(0.766)C Co_(0.177)Mo_(0.547)CCo/Mo/C 14./47.85/37.57 14.58/47.85/37.57 13.92/70.05/16.057.5/79.50/12.99 (wt-%) BET 400 415 350 340 surface area (m²/g) pH 8 9 99 Precipitant 11.6 5.6 5.6 5.6 conc (M) H₂:CO 1 1 1 1 1 CO 41 23 28 2117 Conversion (mole-%) CO₂ 35.46 0.58 3.8 7.5 11.5 CH₄ 9.19 2.7 1.27 1215.3 C₂-C₆ 26.89 2.45 1 15.5 25 Methanol 10.6 19.68 26.21 17.5 13.5ethanol 20.56 21.4 30.7 21 16.3 propanol 21.56 24.9 33.6 22 15 1-butanol5.37 24.96 2 2.5 1.5 higher 9.16 3.33 3.8 2 1.9 alcohols total 67.2694.27 96.31 65 48.2 ALCOH

Table 1 clearly shows that the catalyst of the present invention has asignificantly increased selectivity for methanol when compared to aconventional carbon supported cobalt molybdenum catalyst. In additionthereto, a decrease in CO₂ formation could be observed, which is anundesired side-products produced in F-T synthesis. The selectivitypattern of alcohols also depends on the pH of precipitation mixture andthe concentration of precipitant, wherein the selectivity for methanol,ethanol and propanol is increased in case the pH of the precipitationmixture is increase from 8 to 9.

FIGS. 1 and 2 show XRD pattern of two catalysts prepared at different pH8 (Example 2) and pH 9 (Example 3). The pH difference and concentrationof the precipitant also affects the morphology of catalyst material. Thecatalyst prepared at pH 8 precipitated with more concentrated solutionof ammonium hydroxide was found to be more crystalline and the oneprepared at pH 9 with less concentrated solution of ammonium hydroxideshowed an amorphous morphology. The XRD data were obtained usingstandard X-ray diffraction meter at 2 theta value from 1 to 100 within 1hr.

EXAMPLE 6

Co_(0.126)Mo_(0.255)C

100 ml each of Co and Mo solutions was prepared by dissolving 10.5 g ofcobalt acetate [Co(CH₃CO₂)₂] and 15 g of ammonium molybdate tetrahydrate[(NH₄)6Mo₇O₂₄.4H₂O] in distilled water. Both solutions were premixed andheated to 80° C. The NH3 precipitating solution (200 ml of 5.6M NH₃solution) was also preheated to 80° C. 4g of activated carbon (derivedfrom coconut shell having a BET surface area of 800 m²/g) was added into100 ml of distilled water in the precipitation vessel. Both reagents(mixed metal salts solutions and NH₃ solution) were combined together inthe reaction vessel at 80° C. at a combined pumping rate of 6.7 ml/min(3.3 ml/min NH₃ solution, 3.3 ml/min metals solution). The reagents werecombined in the reaction vessel (80° C.) containing activated carbon in100 ml of water. The pH was varied from 4.35-9.00. The duration ofreaction was ca. 1 h. This solution was filtered and washed. Theprecipitates were dried at 110° C. for 16 h followed by thermal cookingand activation of catalyst at 400° C. under continuous flow ofhelium/nitrogen for 12 to 24 hrs and used for syngas conversion.

EXAMPLE 7

Co_(0.126)Mo_(0.255)C

100 ml each of Co and Mo solutions was prepared by dissolving 10.5 g ofcobalt acetate [Co(CH₃CO₂)₂] and 15 g of ammonium molybdate tetrahydrate[(NH₄)6Mo₇O₂₄.4H₂O] in distilled water. Both solutions were premixed andheated to 80° C. The NH3 precipitating solution (200 ml of 5.6M NH₃solution) was also preheated to 80° C. 4g of activated carbon (derivedfrom coconut shell having a BET surface area of 800 m²/g) was added into100 ml of distilled water in the precipitation vessel. Both reagents(mixed metal salts solutions and NH₃ solution) were combined together inthe reaction vessel at 80° C. at a combined pumping rate of 6.7 ml/min(3.3 ml/min NH₃ solution, 3.3 ml/min metals solution). The reagents werecombined in the reaction vessel (80° C.) containing activated carbon in100 ml of water. The pH was varied from 4.35-9.00. The duration ofreaction was ca. 1 h. This solution was filtered and washed. Theprecipitates were dried at 110° C. for 16 h followed by thermal cookingand activation of catalyst at 500° C. under continuous flow ofhelium/nitrogen for 12 to 24 hrs and used for syngas conversion.

EXAMPLE 8 (COMPARATIVE EXAMPLE—WO 2010/002618 A1)

Co_(0.126)Mo_(0.255)C

100 ml each of Co and Mo solutions was prepared by dissolving 10.5 g ofcobalt acetate [Co(CH₃CO₂)₂] and 15g of ammonium molybdate tetrahydrate[(NH₄)6Mo₇O₂₄.4H₂O] in distilled water. Both solutions were premixed andheated to 80° C. The NH3 precipitating solution (200 ml of 5.6M NH₃solution) was also preheated to 80° C. 4 g of activated carbon (derivedfrom coconut shell having a BET surface area of 800 m²/g) was added into100 ml of distilled water in the precipitation vessel. Both reagents(mixed metal salts solutions and NH₃ solution) were combined together inthe reaction vessel at 80° C. at a combined pumping rate of 6.7 ml/min(3.3 ml/min NH₃ solution, 3.3 ml/min metals solution). The reagents werecombined in the reaction vessel (80° C.) containing activated carbon in100 ml of water. The pH was varied from 4.35-9.00. The duration ofreaction was ca. 1 h. This solution was filtered and washed. Theprecipitates were dried at 110° C. for 16 h followed by thermal cookingand activation of catalyst at 600° C. under continuous flow ofhelium/nitrogen for 12 to 24 hrs and used for syngas conversion.

EXAMPLE 9 (COMPARATIVE EXAMPLE—WO 2010/002618 A1)

CO_(0.126)Mo_(0.255)C

100 ml each of Co and Mo solutions was prepared by dissolving 10.5 g ofcobalt acetate [Co(CH₃CO₂)₂] and 15 g of ammonium molybdate tetrahydrate[(NH₄)6Mo₇O₂₄.4H₂O] in distilled water. Both solutions were premixed andheated to 80° C. The NH3 precipitating solution (200 ml of 5.6M NH₃solution) was also preheated to 80° C. 4 g of activated carbon (derivedfrom coconut shell having a BET surface area of 800 m²/g) was added into100 ml of distilled water in the precipitation vessel. Both reagents(mixed metal salts solutions and NH₃ solution) were combined together inthe reaction vessel at 80° C. at a combined pumping rate of 6.7 ml/min(3.3 ml/min NH₃ solution, 3.3 ml/min metals solution). The reagents werecombined in the reaction vessel (80° C.) containing activated carbon in100 ml of water. The pH was varied from 4.35-9.00. The duration ofreaction was ca. 1 h. This solution was filtered and washed. Theprecipitates were dried at 110° C. for 16 h followed by thermal cookingand activation of catalyst at 700° C. under continuous flow ofhelium/nitrogen for 12 to 24 hrs and used for syngas conversion.

EXAMPLE 10 (COMPARATIVE EXAMPLE—WO 2010/002618 A1)

Co_(0.126)Mo_(0.255)C

100 ml each of Co and Mo solutions was prepared by dissolving 10.5 g ofcobalt acetate [Co(CH₃CO₂)₂] and 15 g of ammonium molybdate tetrahydrate[(NH₄)6Mo₇O₂₄.4H₂O] in distilled water. Both solutions were premixed andheated to 80° C. The NH3 precipitating solution (200 ml of 5.6M NH₃solution) was also preheated to 80° C. 4 g of activated carbon (derivedfrom coconut shell) was added into 100 ml of distilled water in theprecipitation vessel. Both reagents (mixed metal salts solutions and NH₃solution) were combined together in the reaction vessel at 80° C. at acombined pumping rate of 6.7 ml/min (3.3 ml/min NH₃ solution, 3.3 ml/minmetals solution). The reagents were combined in the reaction vessel (80°C.) containing activated carbon in 100 ml of water. The pH was variedfrom 4.35-9.00. The duration of reaction was ca. 1 h. This solution wasfiltered and washed. The precipitates were dried at 110° C. for 16 hfollowed by thermal cooking and activation of catalyst at 800° C. undercontinuous flow of helium/nitrogen for 12 to 24 hrs and used for syngasconversion.

Catalyst Testing

The comparative catalysts were tested under similar reaction conditionsas the catalysts according to the present invention (T=250° C.; p=75bar; and WHSV=1225 h⁻¹). The composition of the feedstream wasCO:H₂:N₂=47.5:47.5:5. Accordingly, the feedstream comprised syngashaving CO:H₂ molar ratio of 1.

TABLE 2 Example 6 7 8 9 10 Catalyst Co_(0.126)Mo_(0.255)CCo_(0.126)Mo_(0.255)C Co_(0.126)Mo_(0.255)C Co_(0.126)Mo_(0.255)CCo_(0.126)Mo_(0.255)C Co/Mo/C (wt-%) 15.88/56.42/27.69 15.88/56.42/27.6915.88/56.42/27.69 15.88/56.42/27.69 15.88/56.42/27.69 pH 9 9 9 9 9Precipitant 5.6 5.6 5.6 5.6 5.6 conc (M) H₂:CO 1 1 1 1 1 BET (m²/g) 366351 311 267 210 CO Conversion 39.8 36.5 24.3 19 11 (mole-%) CO₂ 5 8.311.5 21.6 35 CH₄ 15.5 11 5.2 5.4 2.3 C₂-C₆ 21 13 32 36 41 Methanol 2118.5 19 19.7 11.2 ethanol 25.3 30.1 22 9.6 5.4 propanol 9 16.6 9.1 4.55.1 1-butanol 3.2 2.5 1.2 3.2 0 total alcohols 59.1 67.7 51.3 37 21.7

Table 2 clearly shows that the catalyst of the present invention has adramatically improved CO conversion in combination with a significantlyincreased selectivity for alcohols when compared to a carbon supportedcarbon supported cobalt molybdenum catalyst having a lower BET surfacearea, like the catalyst suggested in WO 2010/002618 A1. Moreover, it isevident from Table 2 that a lower calcination temperature is to beselected when preparing the carbon supported cobalt molybdenum catalyst.

The invention claimed is:
 1. A catalyst composition comprising formulaCo_(a)Mo_(b)M_(c)C, wherein M is one or more elements selected from thegroup consisting of alkali metal and alkaline earth metal and C is anactivated carbon support, wherein the relative molar ratios of theelements in the formula are as follows: a is 1E−3-0.3; b is 1E−3-0.9; cis 0-1E−2; and wherein the Co and Mo are in their metallic form andwherein the catalyst composition has a BET surface area of at least 320m²/g.
 2. The catalyst composition according to claim 1, wherein M ispresent and is selected from the group consisting of potassium (K),sodium (Na), calcium (Ca), and magnesium (Mg).
 3. The catalystcomposition according to claim 1, wherein: a is 1E−2-0.3; and b is5E−3-0.9.
 4. The catalyst composition according to claim 1, wherein thecatalyst composition has a BET surface area of 350-1200 m²/g.
 5. Thecatalyst composition according to claim 1, wherein the Co and/or Mo arenot in sulphide form.
 6. The catalyst composition according to claim 1,wherein said catalyst composition further comprises an inert binder. 7.The catalyst composition according to claim 1, wherein the catalystcomposition has a BET surface area of 350-800 m²/g.
 8. The catalystcomposition according to claim 1, wherein b is 1E−2-0.3.
 9. The catalystcomposition according to claim 1, wherein b is 5E−3-0.2.
 10. Thecatalyst composition according to claim 1, wherein c is >0-1E−2.
 11. Thecatalyst composition according to claim 1, wherein the molar ratio ofCo:Mo is 1.2-4.
 12. The catalyst composition according to claim 1,wherein the molar ratio of Co:Mo is 2.0-2.5.
 13. The catalystcomposition according to claim 1, wherein M is present and is selectedfrom the group consisting of calcium (Ca), and magnesium (Mg).
 14. Acatalyst composition comprising a formula consisting essentially ofCo_(a)Mo_(b)M_(c)C, wherein M is one or more elements selected from thegroup consisting of alkali metal and alkaline earth metal and C is anactivated carbon support, wherein the relative molar ratios of theelements in the formula are as follows: a is 1E−3-0.3; b is 1E−3-0.9; cis 0-1E−2; and wherein the Co and Mo are in their metallic form andwherein the catalyst composition has a BET surface area of at least 320m²/g.